Trans-Selective Olefination of Carbonyl Compounds by Low-Valent Titanium-Mediated Dehydroxybenzotriazolylation
摘要:
Lithiation with n-butyllithium of a variety of benzotriazole derivatives 1a-f and 5a-d, all containing a proton alpha to the benzotriazolyl moiety, gave anions which underwent addition to aliphatic, aromatic, and alpha,beta-unsaturated aldehydes and cyclic and acyclic ketones. The resultant N-(beta-hydroxyalkyl)benzotriazole derivatives 3a-m, 6a-g, 9a-d, and 10a were dehydroxybenzotriazolylated when treated with low-valent titanium to give alkenes 4a-m, dienes 7a-j, and triene 11a, with selectivity for the trans isomers without separation of diastereoisomeric intermediates. This method offers an alternative to the three most frequently used methods for the formation of alkenes from carbonyl compounds-the Wittig, Peterson, and Julia reactions-especially in the formation of tri- and tetrasubstituted alkenes.
Oxygenation of Styrenes Catalyzed by N-Doped Carbon Incarcerated Cobalt Nanoparticles
作者:Tomohiro Yasukawa、Shū Kobayashi
DOI:10.1246/bcsj.20190251
日期:2019.12.15
We found that cobalt nanoparticle catalysts supported on nitrogen-doped carbon could facilitate oxygenation of styrenes in a heterogeneous manner. Both the nitrogen dopant and cobalt species were e...
Photo-induced Decarboxylative Heck-Type Coupling of Unactivated Aliphatic Acids and Terminal Alkenes in the Absence of Sacrificial Hydrogen Acceptors
作者:Hui Cao、Heming Jiang、Hongyu Feng、Jeric Mun Chung Kwan、Xiaogang Liu、Jie Wu
DOI:10.1021/jacs.8b11218
日期:2018.11.28
boronates are among the most versatile building blocks that can be found in every sector of chemical science. We herein report a noble-metal-free method of accessing such olefins through a photo-induced decarboxylative Heck-type coupling using alkyl carboxylic acids, one of the most ubiquitous building blocks, as the feedstocks. This transformation was achieved in the absence of external oxidants through
1,2-二取代的烯烃,如乙烯基芳烃、乙烯基硅烷和乙烯基硼酸酯,是化学科学各个领域中最通用的结构单元。我们在此报告了一种无贵金属的方法,该方法使用烷基羧酸(最普遍的结构单元之一)作为原料,通过光诱导脱羧 Heck 型偶联获得此类烯烃。这种转变是在没有外部氧化剂的情况下通过有机光氧化还原催化剂和钴肟催化剂的协同组合实现的,H2 和 CO2 作为唯一的副产物。控制实验和 DFT 计算都支持基于自由基的机制,最终导致开发出脂肪族羧酸、丙烯酸酯和乙烯基芳烃的选择性三组分偶联。
Synthesis of Substituted 1,3-Dienes by the Reaction of Alkenesulfonyl Chlorides with Olefins Catalyzed by a Ruthenium(II) Complex
Alkenesulfonyl chlorides reacted with vinylarenes in the presence of a catalytic amount of dichlorotris(triphenylphosphine)ruthenium(II) to give substituted 1:1 adducts, which were dehydrochlorinated and desulfonylated successively to form substituted (E,E)-1,3-dienes in good yield.
在催化量的二氯三(三苯基膦)钌 (II) 存在下,烯磺酰氯与乙烯基芳烃反应生成取代的 1:1 加合物,这些加合物依次脱氯化氢和脱磺酰化生成取代的 (E,E)-1,3-二烯良好的产量。
Catalytically Generated Allyl Cu(I) Intermediate via Cyclopropene Ring-Opening Coupling en Route to Allylphosphonates
作者:Zhanyu Li、Guochun Peng、Jinbo Zhao、Qian Zhang
DOI:10.1021/acs.orglett.6b02307
日期:2016.10.7
functionalized allyl copper(I) species via cyclopropene ring-opening coupling reaction is reported, which enables stereoselective access to allylphosphonates. Mechanistic studies uncovered stereochemistry to be controlled by both ligand and substrate electronics, with the latter likely arising from pronounced arene-Cu(I) interaction in electron-deficient substrates. The study unravels a novel approach to